The Ring Index, page 155 (second edition, American Chemical Society, 1960) gives the basic imidazo[1,2-c]pyrimidine structure with a reference to Ann., 432, 120 (1923). Substituted imidazo[1,2-c]pyrimidines are also referred to in the more recent literature; for example, Bartholomew, et al. J. Med. Chem., 19, 814 (1976) gives the preparation of the arabinosyl hypoxanthine and arabinosyl guanine analogs of the imidazo[1,2-c]pyrimidine series. The intermediate compound 7-chloroimidazo[1,2-c]pyrimidine-5(6H)-one is also referred to. None of the compounds disclosed in this publication exhibited significant anti-viral or anti-microbial activity in vitro. West German Pat. No. 2511316 issued Sept. 18, 1975, (Derwent Abstract 64314W/39, 1975) to Eisai KK discloses a group of 2-alkyl-5-alkylmercapto-7-hydroxyimidazo[1,2-c]pyrimidines. They are alleged to be useful as anti-inflammatory or analgesic agents.
A single reference to chloro substituted 2,3-dihydro-imidazo[1,2-c]pyrimidines is available;--see Yanai et al. Yakugaku Zasshi, 94, 1503, (1974). Compound XVII on page 1506 is 7-chloro-2,3-dihydroimidazo[1,2-c]pyrimidine hydrochloride. Both the hydrochloride salt and the free base are characterized in Tables I and Table V and analytical data are provided in Table VIII. The corresponding unhydrogenated compound, XXXII, is also disclosed. No utility is set forth therein for these compounds.